Performance of spent iron-based catalyst in the photo assisted electrochemical system for the removal of methylene blue (MB) dye

This study explores the efficacy of a spent iron-based (Fe.S) catalyst for the photo-assisted electrochemical for removal of Methylene Blue (MB) dye. The catalyst performance was assessed under various operational parameters, including catalyst loading, initial solution pH, current density, and initial dye concentration. The commercial iron oxide (Fe3O4) performance was benchmarked against spent iron-based catalyst under similar operational conditions. The results revealed that the best catalyst dosage was found at 0.02 g and 0.06 g for Fe.S and Fe3O4, respectively. Interestingly, the Fe.S achieved complete MB decolorization, surpassing Fe3O4 which only reached 75% under similar conditions. To support these comparative performances, the catalysts were characterized using SEM-EDX, XRD, FTIR, and BET analyses. After five cycles of reusability, the Fe.S maintained complete removal of MB, whereas the Fe3O4 reusability maintained 45% after three cycles. However, Fe.S experienced leaching of metal ions concentration range 0.1 – 0.5 mgL-1, which is exceed the allowable regulatory limits. Overall, the study highlights the potential of Fe.S for efficient MB dye removal. Nonetheless, the metal leaching concern must be resolved prior to practical application.